Monoperoxyphthalic acid (MPA) has low detonability, good water solubility and general utility as an oxidant and bleach.
MPA may be prepared as a solution in various solvents by the reaction of hydrogen peroxide and phthalic anhydride with or without a basic catalyst (see; Swern, Daniel, ed. Organic Peroxides Wiley-Interscience Publ., New York, New York 1970 pages 424-427 and U.S. Pat. No. 2,273,774 to Reichert, J.S.).
Synthesis of MPA in non-solvents using basic catalyst permits convenient recovery of product as a precipitate (see; U.S. Pat. No. 3,510,512 to Jourdan-Laforte, E.).
Both solvent and base catalyzed non-solvent reaction mediums for MPA synthesis have disadvantages. Processes which employ solvents require the extra step of solvent removal or product extraction. Processes which use basic catalysts impart instability to the MPA product and subsequent attempts to neutralize the catalyst do not give the desired improvement in stability.